This invention relates to a method of and apparatus for automatically inspecting whether chip components mounted on a printed circuit board have been set correctly or not.
Recently, there has been a rapid progress in the technology for mounting chip components on the surface of a printed circuit board and many highly reliable high-speed, automatic mounting apparatus are currently in use. To determine whether components have actually been mounted correctly, however, it is still the visual inspection that is frequently relied upon. With the progress in surface mounting technologies for printed circuit boards, chip components are mounted at higher densities and the components themselves are becoming smaller. As a result, conventional testing methods by visual inspection are no longer sufficiently reliable or efficient. Moreover, as persons who inspect products become tired both physically and mentally, they cannot be expected to give judgments under the same criteria and there are inevitably individual differences among the inspectors.